When Anwar al-Awlaki walked out of a home in the northern Yemeni town of Khashef and stepped into a Toyota pickup Friday morning, he had finally entered the crosshairs of an armed drone that flew noiselessly overhead.

Few violent jihadists had been hunted more assiduously than Awlaki, a U.S. citizen who through his reported role in a succession of plots targeting the United States had risen near the top of the list of American terrorist targets. Yet he had evaded several airstrikes aimed at him.

Friday’s CIA drone strike, which killed Awlaki and a second American, came after days of careful surveillance and many months of searching. It stripped al-Qaeda in the Arabian Peninsula of two of its major propagandists and proponents of hitting Western targets, according to intelligence officials and terrorism experts.

But those individuals also cautioned that the group, which has a number of prominent members with a deep hatred for the United States, will continue to seize any opportunity to wound the West.

“Eliminating any single person doesn’t have a game-changing impact, and this won’t. But it’s a significant strike against al-Qaeda,” said Rep. Adam B. Schiff (D-Calif.), a member of the House intelligence committee. Awlaki “had an almost unique ability to reach out to Westerners — he was good with technology, he was a good propagandist, he understood Western culture, and he could attract people that could travel with U.S. passports.”

U.S. officials said that Awlaki’s operational role and the imminence of the threat he posed led them in early 2010 to place him on a capture or kill list. Yet he proved to be an elusive target.

Awlaki, who was born in New Mexico, was the scion of a powerful tribe in southern Yemen and was presumed to be hiding in the protective embrace of his extended family. But a senior U.S. official said Awlaki, 40, seldom lived in the south, even though his tribe, the Awlak, wielded influence there. He moved between several locations in the provinces of Jawf and Marib, two al-Qaeda strongholds east of the capital, Sanaa.

“He occasionally went south, but generally speaking, his base was in the north, in Jawf and Marib,” said the official, speaking on the condition of anonymity to discuss intelligence matters. “The Awlak tribe is in the south, but he wasn’t there. He was up north.”

The official said Awlaki was meticulous about leaving no electronic fingerprints. He didn’t talk on the phone or take other actions that would have betrayed his position.

“He was a careful guy,” the senior U.S. official said. “He exercised good operational security. He was a hard target.”

U.S. officials said cooperation with Yemeni security agencies has improved significantly in recent months despite rising political instability in the country. The Yemenis, after questioning a suspect, passed on information about Awlaki’s general whereabouts.

U.S. intelligence began to watch from the sky, and local tribal leaders in Jawf province said that in recent weeks they began to suspect, from faint visual cues, that there were drones operating more frequently above them.

The United States eventually zeroed in on the town of Khashef. Awlaki was staying in the house of Khamis bin Arfaaj, a prominent local Islamist who once ran for the Yemeni parliament for the Islah party. The Yemeni government has insisted that the Islah party, one of the country’s major opposition groups, has recently increased its ties to al-Qaeda in the Arabian Peninsula, also known as AQAP. Opposition leaders have denied that assertion.

U.S. officials said that after they identified Awlaki’s exact location, an immediate strike was not possible because he was living among civilians, including women and children.

But on Friday morning, Awlaki and three other men, including the brother of Awlaki’s host, rode in the Toyota pickup outside Khashef. They were five miles away when the missiles struck.

Also killed alongside Awlaki was Samir Khan, a 25-year-old American editor of Inspire, al-Qaeda’s English-language Web magazine, which seemed designed to galvanize potential recruits across the West, particularly in the United States.

Al-Qaeda’s affiliate in Yemen is composed of hard-core locals with years of militant opposition to the central government, Saudi jihadists on the run and focused on overthrowing the royal family, and a mélange of other foreigners.

“AQAP’s shift from a local target set to an international target set was because of Awlaki, who was so focused on the West,” said Christopher Boucek, an expert on Yemen at the Carnegie Endowment for International Peace. “Without Awlaki and Samir Khan, there is no one obvious person who fills that gap. But it’s a very opportunist group.”

Since 2009, Awlaki has been linked, either as a charismatic recruiter or an operational hand, to a host of plots: the Fort Hood shooting by Army Maj. Nidal Hasan, who killed 13 people; the attempted Christmas Day bombing of a plane over Detroit by a man with explosives hidden in his underwear; the plan to bring down two cargo jets over the United States with timed bombs hidden in packages; and the failed attempt to explode a car bomb in Times Square.

U.S. officials said they have been unable to confirm early reports that a Saudi bombmaker, Ibrahim Hassan al-Asiri, was killed as well in Friday’s drone strike. He reportedly created the innovative explosive devices used in the Christmas Day and cargo plane plots.

Through his popular sermonizing on the Internet, Awlaki seemed able to animate just about every other self-radicalizing individual in the United States. And he became a prominent, some said outsize, enemy of the state.

“He was someone who stuck in the eye of the United States,” said Bruce Hoffman, a terrorism expert at Georgetown University. “He was a citizen, he understood and was conversant in our fears and anxieties, and could manipulate them.”

But Hoffman doubts that the United States will become less of a target for AQAP with Awlaki dead. He noted that part of the group’s leadership was held at Guantanamo Bay, Cuba, and that they have “an implacable, visceral desire to get revenge for their treatment.”

“With AQAP’s hard core, it’s very personal when it comes to the United States,” Hoffman said.

Bruce Riedel, a former CIA analyst and terrorism expert, agreed that AQAP will likely remain focused on U.S. targets.

“I’m not sure how much AQAP will continue to be interested in a glitzy English-language Web journal,” Riedel said. “But it’s still going to be interested in attacking the United States.”

He noted that the group’s commander, Nasir al-Wuhayshi, was previously a bodyguard for Osama bin Laden and embraced the former al-Qaeda chief’s focus on the United States and the West. “He was sitting with bin Laden on Sept. 11 when the World Trade Center came down,” Riedel said. “He’s as committed to attacking the United States as anyone else was.”

Raghavan reported from Sanaa, Yemen. Staff writer Greg Miller contributed to this report.